Structures of topoisomerase V in complex with DNA reveal unusual DNA-binding mode and novel relaxation mechanism

Amy Osterman, Alfonso Mondragón*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Topoisomerase V is a unique topoisomerase that combines DNA repair and topoisom-erase activities. The enzyme has an unusual arrangement, with a small topoisomerase domain followed by 12 tandem (HhH)2 domains, which include 3 AP lyase repair domains. The uncommon architecture of this enzyme bears no resemblance to any other known topoisomerase. Here, we present structures of topoisomerase V in complex with DNA. The structures show that the (HhH)2 domains wrap around the DNA and in this manner appear to act as a processivity factor. There is a conformational change in the protein to expose the topoisomerase active site. The DNA bends sharply to enter the active site, which melts the DNA and probably facilitates relaxation. The structures show a DNA-binding mode not observed before and provide information on the way this atyp-ical topoisomerase relaxes DNA. In common with type IB enzymes, topoisomerase V relaxes DNA using a controlled rotation mechanism, but the structures show that topoisomerase V accomplishes this in different manner. Overall, the structures firmly establish that type IC topoisomerases form a distinct type of topoisomerases, with no similarities to other types at the sequence, structural, or mechanistic level. They represent a completely different solution to DNA relaxation.

Original languageEnglish (US)
Article numbere72702
StatePublished - Aug 2022

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology
  • General Neuroscience


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